haematoma

A discrete internal collection of blood which has leaked from damaged blood vessels. At some sites blood can seep away between layers of tissue, but where there are tighter compartments it remains a circumscribed mass which can cause problems by putting pressure on its surroundings. A small one, for example, appears under a fingernail which has been hit with a hammer. At the other extreme a life-threatening one can occur on the surface of the brain (subdural haematoma) following a head injury.

— Stuart Judge

See bruise; haemorrhage.

Haematomas are common sports injuries, often resulting from a collision. A haematoma consists of a swelling caused by accumulation of clotted blood in tissues. The swelling may be inside a muscle (intramuscular haematoma) or outside (intermuscular haematoma). Intramuscular haematomas may be caused by muscle strain, a tear, or bruising. The swelling may press against adjacent nerves, causing pain. It also limits the ability of a muscle to contract and stretch. Intermuscular haematomas cause greater loss of function and a more persistent swelling than intramuscular haematomas. Haematomas require quick treatment by RICE: Resting the affected limb, applying Ice, Compressing the damaged area, and Elevating the damaged limb above the level of the heart.

A swelling caused by the accumulation of clotted blood in tissues. There are two common types of haematoma in sport caused by direct blows or muscle strains: intramuscular haematomas and intermuscular haematomas. They sometimes occur together and can be diagnosed using ultrasound. After treatment with relative rest and ice. a small haematoma may resolve itself. However, a large haematoma may never be reabsorbed (it may develop into a fibrosis and scar. It may be aspirated under aseptic conditions and hyaluronidase may be used to increase the absorption of residual blood. See also black nail, extradural haematoma.